This disclosure relates generally to systems and methods for handling pipes and other elongated tubular members during well drilling, preparation, and maintenance. More particularly, this disclosure relates to systems and methods for handling elongated tubular members in a controlled manner near a drilling platform while inserting or removing the elongated tubular members from a wellbore.
“Tripping” is a term of art used in drilling operations that generally refers to acts of either adding multiple joints of tubular drill pipe to, or removing multiple joints of drill pipe from, a wellbore. Oftentimes during drilling operations, tripping operations may be performed wherein the drill string is pulled from the wellbore in order to change the drill bit, or to run various other types of equipment, such as testing equipment and the like, into the wellbore on the end of the drill string. For example, when tripping drill pipe out of the wellbore, a traveling block and top drive assembly of the drilling or well system may be raised until a stand of drill pipe (i.e., generally multiple connected sections, or joints, of drill pipe) extends above the drilling rig floor. In some cases, a stand of drill pipe may comprise three threaded joints of drill pipe totaling approximately 90 feet in length. Thereafter, slips are placed between the string of drill pipe and the drilling rig floor in order to suspend the drill string in and above the wellbore from a point beneath the bottom threaded joint of the stand of drill pipe that is to be removed from the drill string. In this position, the drill string extends above the drilling rig floor, and the upper end, or box end, of the string is positioned above the plane of a fingerboard suspended above the drilling rig floor on a mast extending upward from the drilling rig floor. In some cases, the fingerboard may be located 75 feet or more above the drilling rig floor.
Once the drill string has been suspended with its box end positioned above the fingerboard, the threaded connection between the stand of drill pipe and the remainder of the drill string is then unthreaded, and the lower end, or pin end, of the stand is guided away from the remainder of the drill string and wellbore and placed on a support pad—sometimes referred to as a setback—on the drilling rig floor. Next, the box end of the stand of drill pipe is removed from the traveling block and the stand is typically manually guided by drilling rig personnel to the fingerboard, where it is staged between a set of racking fingers in a substantially vertical orientation. The top drive assembly is then lowered to the box end of the suspended drill string by the traveling block and coupled to the drill string. Thereafter, the drill string is again lifted to a position where the box end is positioned above the plane of the fingerboard, and the process is repeated until all of the sections of pipe—e.g., in three joint stands—are supported at their respective pin ends on the setback, with their respective box ends being constrained between pairs of racking fingers on the fingerboard. When a new drill bit or other type of tool is being run into the well, the above-described tripping process is reversed and repeated, as the pin end of each stand of drill pipe is threaded into the box end of the drill string, and the drill string is lowered into the well until the drill bit or other tool reaches a desired depth in the wellbore.
The movement of stands of drill pipe from the top drive assembly to the racking fingers of the fingerboard is often manually effectuated by rig personnel, who may pull and/or push the drill pipe to its proper staging location. Similarly, the lower end of the pipe stand being tripped out of the wellbore is also supported and guided manually by rig personnel on the drilling rig floor. It is known that such movements of large sections of drill pipe may involve a variety of difficulties that, if not properly addressed by rig personnel involved in the work, may be hazardous to those personnel, both those working on the rig floor and those near the fingerboard, who may be nearly 100 feet above the rig floor.